Unfortunately this is a classic case of just coming across to nice/boring over text
After she replied I woulda liked her message and said
Sounds good, I have something early in the morning too
What does she do? Instead of re-engaging with a boring good morning, hope you have a good day, re-engage with something about her work, showing empathy about her getting through her monday, or anything relevant to her that she would actually want to respond to
At this point I'd hit her with "I genuinely didn't take you for the flakey type"
